Abstract 1698P
Background
PCa is well known to be an androgen-dependent disease. However, estrogens and estrogen receptors alpha and beta (ERα and ERβ) also play an important role in PCa progression. All types of receptors share similar structure and can be activated by same ligands. As so, relative amounts of all receptor types may be important in predicting overall response to therapy, including androgen deprivation. We aimed to assess possible correlations between ERα, ERβ and androgen receptor (AR) expression in clinical PCa samples.
Methods
A training cohort of 31 radical prostatectomy samples was analyzed. Expression was assessed using double immunofluorescence. Primary antibodies used were mouse monoclonal to AR and ERα, rabbit polyclonal to ERβ. Secondary antibodies were labeled with Alexa Fluor 488 and 555 dyes. 3-15 high power fields (HPF, x40) per case were analyzed. Expression was assessed semiquantitatively (0-3 scores) based on the proportion of stained cells and staining intensity with multiplying the resulting numbers to get total staining score (TSS) for each HPF. Mean TSS was then calculated for each case. ERα and ERβ were stained on the same section and assessed in the same HPF, while AR expression was assessed based on per case TSS.
Results
Mean TSS for ERα was 1.28 and 0.40, ERβ – 3.65 and 2.98 in stroma and epithelium, correspondingly and AR 3.04. TSS for stromal and epithelial ERα expression were not correlated, while a strong correlation was seen for ERβ (rSpearman=0.87). When assessing ER subtypes in stroma, there was correlation in stroma (rSpearman=0.49), but not epithelium. As AR staining in stroma was very similar in all cases, only epithelial AR was assessed. No significant correlations were found between epithelial AR with ER subtypes in stroma or epithelium. Direct assessment of AR and ER coexpression was not performed.
Conclusions
Both ER subtypes were more expressed in stroma than epithelium, but expression was lower than that for epithelial AR. Era and ERb levels were correlated in stroma, possibly showing a role for paracrine regulation of PCa growth. AR expression was not significantly correlated with ER subtypes in our cohort. A study with more cases is ongoing to better define possible links between receptors levels and their possible cumulative role in PCa.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
M. Puchinskaya.
Funding
Belarusian Republican Foundation for Fundamental Research, Grants No. M14M-143, M19M-123.
Disclosure
M. Puchinskaya: Financial Interests, Personal, Invited Speaker: Roche.